<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <input type="text" id="inputEl" />
    <script>
      const inputEl = document.getElementById("inputEl");

      inputEl.onkeydown = function (e) {
        console.log(e.keyCode);
        // if (e.key !== "1" || || ) {
        // if (e.key < "a" || e.key > "f") {
        // if (e.key < "0" || e.key > "9") {
        if (e.keyCode < 96 || e.keyCode > 105) {
          e.preventDefault();
        }
      };
    </script>
  </body>
</html>
